Bill charging method based on inner product encryption for smart power grid

Abstract

The invention relates to the technical field of intelligent power grid privacy protection, in particular to an intelligent power grid-oriented bill charging method based on inner product encryption, which comprises the following steps that: a KDC server generates public parameters and public and private keys, and an intelligent electric meter end generates a certificateless ring signature after collecting user data according to a load monitoring period; in order to ensure that a unique random number is generated in a non-linkability manner, and packaged data containing power consumption data is sent to an aggregator. And the aggregator performs batch signature verification after receiving the packaged data, aggregates the data qualified in signature verification to obtain partial region load data, and sends data including a timestamp, an ID and load information to the block chain. And the intelligent electric meter obtains the public key and the private key and stores the public key and the private key as an electric power data vector according to a charging period, the electric power data vector and a real-time electric power price vector are subjected to inner product encryption to obtain a ciphertext, and after the ciphertext is signed, the packed data is sent to the block chain. And after the block chain receives the data, batch signature verification is carried out, and the ciphertext load and the bill are decrypted, so that the load data and bill information of the whole area are obtained. In the whole process, the load data and the bill data are stored on the block chain, and it is guaranteed that the key data are open and transparent and cannot be tampered.

Description

Technical Field

[0001] The present invention relates to the field of smart grid security and privacy technology, and in particular to a smart grid-oriented billing method based on inner product encryption. Background Art

[0002] Smart grids (SMs) are widely considered to be an efficient solution to reduce carbon emissions and cope with energy crises. Within this framework, collecting user metering data is essential to improve energy efficiency. However, frequent collection of real-time metering data brings huge challenges in terms of data privacy and communication overhead. Initially, user privacy was not taken into account, resulting in malicious attackers linking users' power consumption information with their real information, posing a great threat to users' safety and property. Under the protection of user privacy, dynamic billing is considered, where fine-grained readings collected by smart meters are sent to the operation center (SO) to monitor user loads, effectively control energy supply and consumers' bills, which follow a dynamic pricing approach, where the price of electricity consumption changes in real time throughout the day to incentivize consumers to reduce consumption during peak hours. Most of the existing anonymous aggregated billing schemes that protect the privacy of smart meter users do not consider lightweight and efficiency issues. Smart meters (SMs) have limited computing power, and many schemes have a linear relationship between the computing cost and communication overhead in the authentication process with the number of users, consuming limited resources and being inefficient.

[0003] How to solve the problem of data security and ensure the security and efficiency of aggregated data and billing in the aggregation state has been studied by many research institutes. An et al. proposed a data aggregation scheme based on distributed computing. Through the collaboration between smart meters and data aggregation nodes, the aggregation and billing of power consumption data are realized, and the security against internal adversaries in smart grids is provided. In the existing billing scheme based on homomorphic encryption, a third party is usually introduced to calculate the electricity bill, which leads to huge computational overhead. Zhao et al. proposed a data aggregation and real-time electricity price billing scheme based on homomorphic encryption. The local gateway uses a hybrid multiplication homomorphic algorithm for billing, which greatly reduces the system overhead and does not require the participation of a third party or power supplier to reduce the computational cost. Some research on data security has been conducted using blockchain technology. Zhao et al. used an improved functional encryption scheme for load monitoring while protecting the privacy of consumers; used blockchain to distribute consumer data and solve security issues such as data tampering.

[0004] SMs are devices with limited computing power, so their communication and computational overhead are also major issues. Lightweight encryption systems should be used to ensure consumer privacy and information security. Many researchers have given their own solutions. Sha et al. provided a security framework for smart meters that relies on authentication in two processes. It should be noted that the authentication process only supports authentication of each smart meter one by one, and the computational cost and communication overhead are linearly related to the number of users. Wu et al. proposed some other studies to achieve efficient and fault-tolerant data aggregation, however, additional overhead is required. Fouda et al. proposed a lightweight encryption algorithm and authentication mechanism used in smart grids to reduce computational and communication overhead. Summary of the invention

[0005] The purpose of the present invention is to provide a billing method based on inner product encryption for smart grid, which aims to meet the needs of identity authentication and privacy protection in existing smart grids and realize the functions of user load monitoring and billing in the region.

[0006] The objective of the present invention is achieved through the following technical solutions: Step 1: In the initialization phase, the KDC server initializes public parameters and generates public and private keys; Step 2: User and aggregator registration: smart meter users and aggregators send their IDs for registration respectively; Step 3: User power information collection report: The smart meter collects power data every 30 minutes. Legitimate users generate a certificateless ring signature for the data message and package the relevant information and send it to the aggregator. Step 4: In the data aggregation stage, the aggregator first verifies the timestamp and batch verifies the signature. Each aggregator that passes the verification aggregates the consumption readings and packages them to the blockchain; Step 5: In the billing stage, the smart meter stores the power information collected according to the billing cycle in a vector and performs inner product encryption with the power price vector to obtain the bill ciphertext, which is then packaged and sent directly to the blockchain. The system operation center receives the load information and bill information from the blockchain and aggregates and decrypts them to obtain the total power consumption and power consumption information. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0008] Figure 1 This is a system model diagram of the billing method based on inner product encryption described in an embodiment of the present invention. Figure 2 This is a flow chart for load monitoring and billing. Specific implementation

[0009] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] The billing method based on inner product encryption for smart grids described in the embodiment of the present invention comprises the following steps: 1) Initialization system: The process of initializing public parameters and generating public and private keys by the KDC server. Specifically, the KDC server selects two groups (G1,+) and (G1,*) of a prime number q, g1 is the generator of group G1, g2 is the generator of group G2, e is the bilinear pairing e:G1×G1"G2, and selects the master private key Calculate the master public key Select another global hash function H1: And the hash function H2: The KDC server uploads the public parameters par=(q,g1,g2,G1,G2,e,H1,H2) to the blockchain and secretly saves the public and private keys msk and mpk. 2) Smart Meter and Aggregator Registration: During the user registration process, smart grid users SM i and Aggregator AG j Provide the user's identity identifier ID to the KDC server i and ID j , the KDC server is the user SM i Generate pseudonymous FID i and the partial private key psk i And return it to the smart meter through a secure channel; after the smart meter user passes the verification, it generates a public-private key pair (ppk i ,psk i ). In similar aggregator registrations, aggregator AG j Provide the smart meter's ID to the KDC server j , then the aggregator generates the public and private keys (FID j ,ppk j ). 3) Power information reporting stage: User power data reporting requires the smart meters in the area to transmit their user IDs to KDC, and power consumption data d i Collected every 30 minutes, smart meter SMi Calculate q i and Q i , and passes the value to the KDC. KDC calculates the partial private key psk i And provide it to other ring members, SM i Generate a key pair (sk i ,pk i ), ID i Anonymous private key sk i Signed message d i Then output the certificateless ring signature σ i =(U i ,V i ). Then SM i Messages are processed to prevent numbers generated by the same user at different timestamps from being linked together. i is calculated as Among them A i is a pseudo-random number, B i is the counter value. So the last single smart meter SM i The power consumption information is " i =d i ||R i ||t i ||σ i , t i is the current timestamp. i The consumption information report Λ generated at the corresponding timestamp i In addition, each SM i Set the billing cycle to T A The readings within are stored in the vector r i C =[r i [1],...,r i [b]] T . 4) Aggregation phase: When the aggregator AG receives the power consumption information Λ i , verify the timestamp, and then batch-check the signature of the message. If the verification passes, the AG accepts the message, otherwise it rejects the message. j The received readings are aggregated to obtain all AG j Total electricity consumption in the area Then AG j The power consumption value E of each area at that moment i ||ts i ||ID j Sent to the blockchain, ID j is the ID of the aggregator, ts iis the timestamp. SO gets each AG from the blockchain j After the power information is transmitted, the load values ​​of all AG areas are summed to obtain the total load data 5) Billing stage: During the electricity billing process, SM i First, the reading m in the previously stored billing cycle is i =[m1,...,m b ] is encrypted to obtain the ciphertext CT i , followed by SM i Generate timestamp ts i =H1(l t ) to resist replay attacks, l t is the identifier of the current time, SM i Generate signature δ through BLS algorithm i =t i "H2(CT i ||ts i ||mpk i ). When receiving a charging request from SO, SM i Generate the (j+1)th block and add the jth block to the blockchain after the (j-1)th block through the Merkle tree. The content sent is M i =CT i ||ts i ||mpk i ||ID i ||δ i When SO receives M from the blockchain i , SO verifies the timestamp of each message and batch verifies the signature message. For the verified message, SO performs hash operation to generate the Merkle tree root hash value, and then SO generates a new block Block and broadcasts it to other SMs in the area. After receiving the block, SM verifies the block hash value, timestamp and data, and sends the verification result to other SMs to achieve mutual supervision between SMs. SO performs decryption operation Dec(sk y ,CT i ), get the electricity bill y i is the real-time dynamic electricity price vector. This paper proposes a billing method based on inner product encryption for smart grid to solve the problems of low security and efficiency, enable the system operation center to monitor the load and calculate the bill, and protect the privacy of users. In the load monitoring stage, certificateless ring signature and unique random identifier are used to ensure the security of power data. In addition, we use improved functional encryption to protect the user's electricity bill data. The privacy of users is protected in the ciphertext state.

Claims

1. A billing method based on inner product encryption for smart grid, characterized in that: The following steps are involved: Step 1: In the initialization phase, the KDC server initializes public parameters and generates public and private keys; Step 2: User and aggregator registration: smart meter users and aggregators send their IDs for registration respectively; Step 3: User power information collection report: The smart meter collects power data every 30 minutes. Legitimate users generate a certificateless ring signature for the data message and package the relevant information and send it to the aggregator. Step 4: In the data aggregation stage, the aggregator first verifies the timestamp and batch verifies the signature. Each aggregator that passes the verification aggregates the consumption readings and packages them to the blockchain; Step 5: In the billing stage, the smart meter stores the power information collected according to the billing cycle in a vector and performs inner product encryption with the power price vector to obtain the bill ciphertext, which is then packaged and sent directly to the blockchain. The system operation center receives the load information and bill information from the blockchain and aggregates and decrypts them to obtain the total power consumption and power consumption information. The billing method based on inner product encryption for smart grid according to claim 1 is characterized in that: The execution body of the billing method based on inner product encryption for smart grid includes a KDC server, a smart meter SM i , Aggregator AG j , operation center SO and blockchain, the blockchain is responsible for recording the KDC server, the user smart meter SM i and Aggregator AG j And data between the operation center SO.

2. The billing method based on inner product encryption for smart grid according to claim 1, characterized in that: The KDC server initializes public parameters and generates public and private keys. Specifically, the KDC server selects two groups (G1, +) and (G1, *) of a prime number q, g1 is the generator of group G1, g2 is the generator of group G2, e is the bilinear pairing e:G1×G1→G2, and selects the master private key Calculate the master public key Choose another global hash function and hash functions The KDC server uploads the public parameters par=(q,g1,g2,G1,G2,e,H1,H2) to the blockchain and secretly saves the public and private keys msk and mpk.

3. The billing method based on inner product encryption for smart grid according to claim 1, characterized in that: During the user registration process, the smart grid user SM i and Aggregator AG j Provide the user's identity identifier ID to the KDC server i and ID j , the KDC server is the user SM i Generate pseudonymous FID i and the partial private key psk i And return it to the smart meter through a secure channel; after the smart meter user passes the verification, it generates a public-private key pair (ppk i ,psk i ). In similar aggregator registrations, aggregator AG j Provide the smart meter's ID to the KDC server j , then the aggregator generates the public and private keys (FID j ,ppk j ).

4. The billing method based on inner product encryption for smart grid according to claim 1, characterized in that: The user power data report requires the smart meters in the area to pass their user IDs to the KDC, and the power consumption data d i Collected every 30 minutes, smart meter SM i Calculate q i and Q i , and passes the value to the KDC. KDC calculates the partial private key psk i And provide it to other ring members, SM i Generate a key pair (sk i ,pk i ), ID i Anonymous private key sk i Signed message d i Then output the certificateless ring signature σ i =(U i ,V i ). Then SM i Messages are processed to prevent numbers generated by the same user at different timestamps from being linked together. i is calculated as Among them A i is a pseudo-random number, B i is the counter value. So the last single smart meter SM i The power consumption information is Λ i =d i ||R i ||t i ||σ i , t i is the current timestamp. i The power consumption information report Λ generated at the corresponding timestamp i In addition, each SM i Set the billing cycle to T A The readings within are stored in the vector 5. The billing method based on inner product encryption for smart grid according to claim 1, characterized in that: When the aggregator AG receives the power consumption information Λ i , verify the timestamp, and then batch-check the signature of the message. If the verification passes, the AG accepts the message, otherwise it rejects the message. j The received readings are aggregated to obtain all AG j Total electricity consumption in the area Then AG j The power consumption value E of each area at that moment i ||ts i ||ID j Sent to the blockchain, ID j is the ID of the aggregator, ts i is the timestamp. SO gets each AG from the blockchain j After the power information is transmitted, the load values ​​of all AG areas are summed to obtain the total load data 6. The billing method based on inner product encryption for smart grid according to claim 1, characterized in that: During the electricity billing process, SM i First, the reading m in the previously stored billing cycle is i =[m1,...,m b ] is encrypted to obtain the ciphertext CT i , followed by SM i Generate timestamp ts i =H1(l t ) to resist replay attacks, l t is the identifier of the current time, SM i Generate signature δ through BLS algorithm i =t i ·H2(CT i ||ts i ||mpk i ). When receiving a charging request from SO, SM i Generate the (j+1)th block and add the jth block to the blockchain after the (j-1)th block through the Merkle tree. The content sent is M i =CT i ||ts i ||mpk i ||ID i ||δ i When SO receives M from the blockchain i , SO verifies the timestamp of each message and batch verifies the signature message. For the verified message, SO performs hash operation to generate the Merkle tree root hash value, and then SO generates a new block Block and broadcasts it to other SMs in the area. After receiving the block, SM verifies the block hash value, timestamp and data, and sends the verification result to other SMs to achieve mutual supervision between SMs. SO performs decryption operation Dec(sk y ,CT i ), get the electricity bill y i is the real-time dynamic electricity price vector.

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